KIEV, Ukraine (AP) — Former Prime Minister Yulia Tymoshenko says Ukraine "must be a member of NATO" in order to protect itself from Russian aggression.

Tymoshenko, who is running in the May 25 presidential election, told The Associated Press in an interview that while only a minority of Ukrainians supported NATO membership previously, Russia's aggressive actions in the country's east had forced a "fundamental change" in public thinking.

She says "with his war against us, (Russian President Vladimir) Putin was able to change the mentality of Ukrainians and turn us in a different strategic direction. NATO is the best choice for Ukraine."

While Tymoshenko hadn't previously backed NATO membership publicly, she and other Ukrainian politicians have ramped up the tough rhetoric as pro-Russia militias seized police stations and government buildings across eastern Ukraine.